1. Related Fields
Related fields include methods of interpolating traffic information data, apparatus for interpolating, and traffic information data structures.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2002-148067 discloses a navigation method of accumulating received traffic information, time and date, and day of the week and finding a shortest route or calculating a travel time with the aid of the accumulated data.
In the aforementioned navigation method, however, the received traffic information is not always normally provided for all the links. Thus, for example, missing data and the like, may occur. Using such unreliable stored data can undermine the reliability of searching route.